A/f ratio for max temperature and pressure 2

[Deividas]

Hello, I was working with one ICE simulation program, and noticed, that in diesel engine, where a/f is 1.75, max combustion pressure is 128.81bar, and max combustion temperature is 2118.1K, and in same engine, where a/f ratio is 1.5, max combustion pressure is 115.71bar, an max ombustion temperature is 1982.2K, if a/f ratio is leaner than 1.75, pressure and temperature also drops. I always thougt, that in diesel, if a/f is richer, pressure and temperature should be higher. So where is point in diesel engine, where combustion pressure and temperature is highest? And why pressure and temperature rops, when going to richer side?

 

[Deividas]

Thank You for answers

 

[Panther140]

Cutoff ratio matters in thermal efficiency of a CI engine. How is that changing in your tests?

"Formal education is a weapon, whose effect depends on who holds it in his hands and at whom it is aimed." ~ Joseph Stalin

 

[Deividas]

Panther140 - that program don't calculate cut-off ratio, so i don't know. But now i'm confused - cut-off ratio is ratio of cylinder volume when injection starts and when injection ends, or it is volume of cumbustion chamber and cylinder volume when injection ends?

 

[Deividas]

"doesn't calculate" - sorry for poor English

 

[gruntguru]

Cylinder volume when injection ends divided by volume of combustion chamber at TDC

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